Racecar Project - Transmission
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
Racecar Project - Transmission
My transmission is now complete. I had my friend Rick Deman of Deman Motorsports put together my transmission and he did an excellent job. I started with a core 98 993 C4 6spd transmission (G64/21) that was stuck in 6th gear, a used 97TT LSD of ebay, bought a new 4.0 R&P, PMNA 40/60 LSD pressure rings, PMNA friction plates, found used 3,4,5,6th gears, 3,4,5,6 steel syncros, new 2nd gear brass syncros (steel are something like $1500 for just 2nd gear), bought a new 2wd end cover, and 996 cup car solid transmission mounts. Rick put all of this together as well as drilled the case for trans cooling lines and a temperature sensor. The trans cooler return line will dump the gear oil directly on the ring gear and differential which should help it live longer. The temp sensor is connected to the MoTeC which will turn on the pump when required. Here are some pictures as well as the gearchart based on 25.5" diameter tires. My 6th gear is slightly taller than a 964 Cup Car 4th gear (G50/10).
Three Wheelin'
Joined: Oct 2002
Posts: 1,879
Likes: 3
From: Pasadena, MD - Land of Taxes
God I love your pictures! I'm sure you can hardly wait until you are rocketing around the track!
Are/were there any issues with the transmission swap? Will the 6-Speed bolt right up in place of the 5-Speed?
Are/were there any issues with the transmission swap? Will the 6-Speed bolt right up in place of the 5-Speed?
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
While I am enjoying the project, I am definately eager to drive the car which is really what I enjoy more than building it.
The 6spd is physically the same length as the 5spd and is a direct bolt in.
The 6spd is physically the same length as the 5spd and is a direct bolt in.
Race Car
Joined: Nov 2004
Posts: 4,951
Likes: 1
From: Wisconsin
If you are club racing, there is a fantastic track in Joliet Illinois, called Autobahn Track. The milwaukee region is sponsoring a club race there in June. I had the extreme pleasure of driving the track on a recon mission down there. What fun!!!!! And if you need a bed while you're in the area, house is open.
Also, since we share the same name, do that get me in the driver's seat?
Also, since we share the same name, do that get me in the driver's seat?
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Rennlist Member
Joined: Jul 2003
Posts: 1,964
Likes: 71
From: Peachtree City, Ga
just for those that may be interested I worked up a spread sheet for various gear ratios -
It is based on a fromula that uses the tire diameter as a start point - I used 24.75 in - so just enter your wheel diameter to change. -
It is an excel spread sheet format so I can't post ( or don't know how) here - but send me your email and I will send direct if you are interested -
I currently have the G50 5 speed / G50 20 and 21 ratios plus other ratios-
aam working on adding the ratios offered by Gear an d will ahve that posted soon -
It is based on a fromula that uses the tire diameter as a start point - I used 24.75 in - so just enter your wheel diameter to change. -
It is an excel spread sheet format so I can't post ( or don't know how) here - but send me your email and I will send direct if you are interested -
I currently have the G50 5 speed / G50 20 and 21 ratios plus other ratios-
aam working on adding the ratios offered by Gear an d will ahve that posted soon -
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Rennlist Member
Joined: Jul 2003
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From: Peachtree City, Ga
Geoffrey- I rereading your notes that you used a C4 G50 and just replaced the end cover with a 2wd end cover - Was this easy ?? or did you have to replace any shafts. Also noticed that it appears that you kept the stock 1st and 2 nd gears - Did you do this becaseu the gears are cut on the mainsahft or ypu wanteed the lower ratios. I am trying to do soemthing similiar, but wanted to start with a G50/21 but raise the first gear to a 2.83 keep 2nd, but change the rest - I have a g50/20 that came out of a wreck and the front and rear cases are cracked so am trying to find replacement - not easy - Like you I grabbed a LSD off of ebay but have not had a chance to get into it yest to see waht I need to do Your looks really good/ as does all your work - very professional -
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
The transmission work was not mine, Rick Deman did the trans disassembly cleaning (big job), inspection and assembly work.
I kept first and second gear because they are on the main shaft. Some early 95s have a removable second gear but around 96 they went to second gear on the mainshaft. I would have liked to have a longer second gear which would make it a little better. It is one of the compromizes in the car due to the cost of a main shaft.
The pinon shaft in the AWD needs to be cut or replaced with a new R&P as I did in order for the C2 end cover to fit.
I kept first and second gear because they are on the main shaft. Some early 95s have a removable second gear but around 96 they went to second gear on the mainshaft. I would have liked to have a longer second gear which would make it a little better. It is one of the compromizes in the car due to the cost of a main shaft.
The pinon shaft in the AWD needs to be cut or replaced with a new R&P as I did in order for the C2 end cover to fit.
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
I also have mounted the transmission oil cooler pump. What you see is a Mocal fluid pump which is the exact same as the Tilton part, they must use the same manufacturer and rebrand them. I included a small Peterson filter with internal replaceable filter assembly to help keep things clean (cool). I have not yet decided where to mount the cooler itself. I'd like it as clean as possible with lines as short as possible, however, I may attempt to put it in the front behind the bumper. I will most likely put dry break fittings on the lines so the trans can be removed without dumping the fluid. Gear oil is one of the smells I like least. I'd rather smell brake cleaner and gasoline.
The pump itself has a cover on the bottom that was broken in shipping so it needs to come back off and I'll obviously use bolts that are a more appropriate length than what you see when I mount it permanently. Also, the yellow comming from between the seams is not rust, but the POR15 or Wurth body wax that I sprayed into all of the open channels after powercoating.
The pump itself has a cover on the bottom that was broken in shipping so it needs to come back off and I'll obviously use bolts that are a more appropriate length than what you see when I mount it permanently. Also, the yellow comming from between the seams is not rust, but the POR15 or Wurth body wax that I sprayed into all of the open channels after powercoating.
Thread Starter
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
Why do you need braided stainless lines? The rubber lines are the one component that PMNA does not suggest changing after a 24 hour race. I have a set of SS lines if anyone is interested. GT3RS cars come with factory 996 ruber lines...go figure. I had SS lines on my 911 Turbo and I really didn't notice any difference.
Registered User
Joined: Oct 2004
Posts: 961
Likes: 1
From: manchester u.k
if your car is inspected regularly (like after every track outing ) why would you want to cover rubber brake lines with a braiding that stops you inspecting them ???????
any advantages that the braiding may offer to stop the rubber hose ballooning , are lost if you are on top of regular inspection and replacement .
any advantages that the braiding may offer to stop the rubber hose ballooning , are lost if you are on top of regular inspection and replacement .